[7][8][9] Clothianidin is authorized for spray, dust, soil drench (for uptake via plant roots), injectable liquid (into tree limbs and trunks, sugar cane stalks etc.

The chemical may be used to protect plants against a wide variety of agricultural pests in many countries, of which the following are mentioned in citable English-language sources: Australia, Austria, Belgium, Bulgaria, Canada, Czech Republic, Denmark, Estonia, France, Finland, Germany, Greece, Hungary, Italy, Ireland, Japan, Korea, Lithuania, Netherlands, New Zealand, Poland, Portugal, Serbia, Slovakia, Slovenia, Spain, UK, and the United States.

It also plays a key role helping to prevent the buildup in insect pests of resistance to organophosphate and pyrethroid pesticides, which is a growing problem in parts of Europe.

However, in response to concerns raised by bee keepers, in November the EPA released a memorandum in which they stated that some of the studies submitted did not appear to be adequate and the unconditional registration was withdrawn.

[27] Beginning in 2006, beekeepers in the United States began to report unexplained losses of hives — 30 percent and upward — leading to a phenomenon called colony collapse disorder (CCD).

[28][29][30][31] The Australian Pesticides and Veterinary Medicines Authority notes that clothianidin ranks "among the most highly acutely toxic insecticides to bees" through contact and oral exposure.

However, in a 2012 statement the EPA reported that they are not aware of any data demonstrating that bee colonies are subject to elevated losses due to long-term exposure when clothianidin products are used at authorized rates.

However, according to the EPA, the use of sticking agents to reduce dust from treated seeds is standard practice in the U.S.[39][40] In a July 2008 German beekill incident, German beekeepers reported that 50 to 100 percent of their hives had been lost after pneumatic equipment used to plant corn seed blew clouds of pesticide dust into the air, which was then pushed by the wind onto neighboring canola fields in which managed bees were performing pollinator services.

[41][42] A report released in 2012 found a close relationship between the deaths of bees and the use of pneumatic drilling machines for the sowing of corn seeds coated with clothianidin and other neonicotinoid insecticides.

Field tests found that foraging bees flying through dust released during the planting of corn seeds coated with neonicotinoid insecticides may encounter exposure high enough to be lethal.

The insecticides were also consistently found at low levels in soil up to two years after treated seed was planted, and on nearby dandelion flowers and corn pollen gathered by the bees.

[45][46] Also in 2012, researchers in Italy published findings that the pneumatic drilling machines that plant corn seeds coated with clothianidin and imidacloprid release large amounts of the pesticide into the air, causing significant mortality in foraging honey bees.

[52] Studies submitted by Bayer AG to USEPA have provided some useful information about clothianidin's potential long-term effects on honey bees but outstanding questions remain.

USEPA's analysis of nine pollinator field studies submitted concluded that three were invalid, so EPA did not use the data they provided in making its regulatory decision for clothianidin.

[23] An international group of pesticide regulators, researchers, industry representatives, and beekeepers is working to develop a study protocol that will definitively answer remaining questions about the potential long-term effects on bee colonies and other pollinators.

[18][10][13] Using laboratory test animals as surrogates for humans and dosages much higher than are expected from exposure related to actual use, rats showed low short-term oral, dermal, and inhalation toxicity to clothianidin.

However, regulatory authorities around the globe emphasize that when used according to the label instructions, clothianidin residues on food are not expected to exceed safe levels (as defined by each nation's laws and regulations).

In a 2010 EPA report, it was noted that the registrant (e.g. Bayer or Takeda) had recently added new uses on the labels, including using the pesticide directly applied to the soil surface/foliage at much higher application rate than as specified in 2003.

However, EPA assessments show that exposure to treated seeds through ingestion may result in chronic toxic risk to non-endangered and endangered small birds (e.g., songbirds).

Worst-case scenario estimates indicate that if applied at the maximum rate repeatedly over years, clothianidin has the potential to accumulate in the top 15 cm of soil.

In 2012, several peer reviewed independent studies were published showing that neonicotinoids, including clothianidin, had previously undetected routes of exposure affecting bees including through dust, pollen, and nectar; that sub-nanogram toxicity resulted in failure to return to the hive without immediate lethality, the primary symptom of colony collapse disorder; and showing environmental persistence in agricultural irrigation channels and soil.

Their review concluded, "A high acute risk to honey bees was identified from exposure via dust drift for the seed treatment uses in maize, oilseed rape and cereals.